Variable speed fan drive



L. D SUTTLE VARIABLE SPEED FAN DRIVE Jan. 14, 1958 4 Sheets- Sheet 1 Filed Jan. 27, 1955 er es W 2 n a 3 a 2 M 1 1.

Jan. 14, 1958 v 1 D. SUTTLE 2,819,703

- VARIABLE SPEED FAN DRIVE Filed Jan. 27, 1955 4 Sheets-Sheet 2 1770977507" jawrence J. fluzfle Jan. 14, 1958 E L. D. SUTTLE 2,

VARIABLE SPEED FAN DRIVE Filed Jan. 27,. 1955 4 Sheets-Sheet 5 I72 veie 202" 5y far/yer 4 Carla)" .lztor'ieeys Jan. 14, 1958 L. D. su'r'rLE ,7

VARIABLE SPEED FAN DRIVE Filed Jan. 27, 1955 4 Sheets-Sheet 4 J52 yenlbr .Zawrence .D. ,Suzfle- VARIABLE SPEED FAN-DRIVE? LaWreneeDLSuttle, Detroit; Michr, assignor to Robert :L- Schalfer, Detroit; Mich:

Applic-ationJanuar-y 27, 1955, SerialNo: 48%345" 8 Claims; (ClI123-41212) disconnectable or'slip-couplin-g type-for use 'with or on then cooling system: of a l vehicles internal combustion engine or the like.

A: primary object of my inventibn-'--is -a new and improve'd fan drive adapted to provide slippage betweenthe fan and: the: engine at a predetermined speed so that at high speeds the fan will- 'not steal-powerfrom the engine;

Another object is a fandrive of the above type adapted to be= driven at-thesame speed as the'engine'up to a predetermined speed after which, as the engine speed'in' Anotber object is a fan-drive of theabovetype in the form ofan attachment usable on or with conventional engines.

Another object isa fan driveof' the "above "type"con= Another object 'is a fan drive of the above'type'which' is quieter in operation at the higherengine speeds.

Another 'object'is 'afan drive of the abovetypere'sponsive to ambient temperatureso that 'in winter" the engine will be allowed to heat 'up more rapidly, and in summerthe engine will'be cooled quicker.

Ahother'object is'a fan drive of the"abov'e type with opposed friction elements to provide slippage'between the'fan'and its drive and including means for coolingjthe friction elements at a rate relative to the engine speed Another 'object'is' a fan and fan drive of the above type whicb'runs at all times that the engine is running, but will n'ot'exceed a predetermined rotative speed regardless of the engine speed;

Other objects willappear from time to time in--the ensuingspecificatiQnand drawings. in which:

Figure l is a side view, partlyin section, .ofQ-my.-new and'improved fan drive;

Figure 2 is a section of a modified form of .fandr'ive;

Figure 3 is afront view partlyin section of the fan diive shown in Figure '1;

Figure 4-is a detail view;

Figure 5"is-a side-view, partly in section, of .a-variant form; and

Figure6 is a front view,- withparts broken away,.of the Figure 5 variant form..

In Fig. 1a suitable pulley or :sheave-10 isadapted to bedriven .by the usual. engine fanbelt, not sbowny-or any other suitable drive. The pulley is connected to a member .12 to drive a conventional water pump through a..water pump..shaft14 and 16.-

A body member 18'is mounted over the forward end of1the..water pumu shaft 1 by a plurality 'of suitable bolts 20Lor the like. The bodymember: is formedrinto aproiecting shaft or stub 22 at its forward end which carries structed so that less-horsepower will be'required'to drive a suitable fan 24. Thefan 24 is rotatably mounted about the stub 22 through a suitable ball bearing unit 26. The" bearing is held in a cageformed by the inner part of the fan'proper, as at 28,- and a cylindrical portion 30 of aplatelike member 32 which is formed upwardly and rearwardly into a suitable sheave or pulley'34 and'has a lip 35 at its inner edge. The member 32 also' carriesa' circularfriction-member or ring 36 on its inner surface; the fan, member-32; and friction-member'36bein'g held together b'y 'a-suitable number of bolts 38 or'the like; which are=spaced around the center of the fan:-

A cuplike'member 40, mountedon the 'body' member" provided with asuitable number of'radial slots''46 as shown iii-Fig: 3, andtliehubbr inner portion ofthe' fan is 'provided' with a suitable number of openings 48which extend through the fan, member 32, and frictionrir'i'g 136; so"thatair-can enter"thespace or chamber betweenthe fan andthe body member;

Tliefan-"and its bearing; unit- 26--'areadapted to' slip on"-the'stub 'orshaft"22" in'an axial direction; anda slid ing 'coll'ar 50 aroundthestubengages the inner race "of thebearingi A-spring"52; held by a snap ring 54whiclr bearsagainst'a shoulder5'6 near the end' of the stubor sliaft 22, biases "the collarand ball bearing unit, as well as'the' ran;- rearwardly sothat thefr'iction plate36" will engagethefriction'segments or elements at all times.

InFi-g.=' 1"I have' *shown'the friction 'elementsdisposed inaplanegenerally, atright angles "to the axis of the-body member and" fang however," the friction elements could "be inclined rea'rwardlyg".as shown "in "Fig; 2 or forwardly"if desired.

In -Figure**5 I-have 'showna variant "form in l which the sheave or pulley 58 is mounted on a memberf60"witli"'a' suitable spacer 62 "or 'the like; ,themember '60 being securedto the -'wate1ffpump'- shaft by. one or more suitable pins "'64. A'- *cup=lik'e member '66"-is'"secur ed" to the body member 68 bya suitable'numb'e'r of bolts .70-"'orthe"'lik'e; thebolts extending *throughthe cup-like member 766', the b'ody'inember'68i the'spacer' 62 endthe memb'er'60f Theflanged portion" 72 of 'the eup'dikemembr carries apliiral'ityof friction elements 74 which are disc shaped; as shown in Figure G 'and are secured to'the'fiangeby'a' suitable-rivet or pin 76 countersunk as at 78 to prevent wear.

The fan 80 is mounted ona friction plate 82by a"suit= ablenumber of rivets 8 3 "or thelike; The inner porti'onof thefriction'plate'isformed at 86% retain the ball bearing unit' 88 mountedwnitheshaft or stub90." The fan and friction plateareprovided 'vvith aligned openings 92"and '94 so'th'at airw'ill beadtitittedtothe inside of the cup shaped member. I

A suit a'ble co1lar9 6on the shaft is biased against." the innerra'ceofthe bearing byoppositelydispbsedBellevill bimetallic spring type' discsfisf'which abut a suitable .lo'ck nut l0tl threaded on thestubshaft and h'eldin' position by *a-suitabl' lockwa'sher "102. A s-shown in'Figure 6, the Bellevi'lle springs are disc shaped and are provided with radialslots 104 to allbw' for expansion and contraction.

The use, operation and function of my invention are as follows I haveshown and ileseribeda fandrive for use with'the engirie ofiawehicl; The fans primary purpose is to cool the engine atvthel'lowe r speeds". Atthehighersp'eeds the moving airrcreated-by' thevehicle cools the engine substantiallyandithe fan isnot-so important.

To get proper coolingof'the engine at the'lower speeds the tfanrhas to be relatively-large in capacity and size; At the higher speeds the noise created by this large fan and the power absorbed by it become excessive. The fan, in a sense, at the higher speeds steals excessive power from the engine which otherwise could be used to propel the vehicle. Clutch-type devices are known which disconnect the fan entirely from the engine at a predetermined enginespeed.

In my new and improved fan drive, at a predetermined speed, slippage occurs between the fan and its vdrive through its friction elements so that, even though the engine reaches higher speeds, the fan will remain at a lower speed.

In my invention a body member having a friction element is attached to the water pump shaft to be driven by the engine and is referred to as the driving member.

A fan is rotatably mounted on the body member and carries another friction element which opposes'the first friction element on the body member. Axial movement or slippage is permitted between the fan and body member so that the pressure between the friction elements can be varied. A spring biases the friction elements together so that a positive rotative drive is established between the body member (the driving member) and the fan (the driven member).

At the lower speeds no slippage will occur between the friction elements so that the fan will be driven at the same speed as the engine. At the higher speeds the fan will tend to thrust forward and slippage will occur between the friction elements because the fan is slidably mounted on the body member. The forward thrust of the fan is opposed by the spring, and the tension exerted by the spring determines the particular speed at which slippage first occurs. As the engine attains speeds in excess of this particular speed, slippage will containue between the friction elements and the fan will tend to remain at a relatively constant speed which is independent of the engine speed.

In setting the top speed of the fan, the tension of the spring, the material used for the friction segments, the material of the plate opposing the segments, the size and thrust of the fan, and other factors must be taken into consideration.

The spring can be formed as a bimetal element so that the force exerted by it will vary dependent upon the ambient temperature. This is particularly advantageous due to the change in temperature from one season to another. For example, in winter when the outside temperature is low, it is desirable that the engine be allowed to warm up as fast as possible, and the fans cooling effect should be reduced. Therefore the bimetal spring should react to the lower temperatures by reducing its force or thrust so that slippage will occur at a lower speed. In the summer when the temperatures are relatively high, more engine cooling is required, and the bimetal spring should respond to the high temperatures so that its force will be increased to cause slippage to occur between the fan and the body member at a higher predetermined speed. Therefore the bimetal spring should be arranged and constructed so that it will exert more force at high temperature and less force at low temperature.

-Whereas I have shown and described my invention as applied to a fan for cooling the engine, it should be understood that various other accessories on modern automobiles also do not require the high engine speeds. A suitable drive, such as through the pulley 34 and a belt, not shown, could be provided running to these accessories so that they too would not be driven in excess of the predetermined speed.

While I have shown the friction surfaces as lying in a plane generally at right angles to the axes of the body member and fan, as in Fig. 1, it should be understood that the plane of these surfaces could be inclined, as in Fig. 2, to increase the effective frictional contact area. At the same time the angle of inclination could be in the opposite direction from that shown in Fig. 2.

The friction eiement 44 carried by the body member is divided by slots into a plurality of frictional segments with the friction ring or disc 36 on the fan bridging these slots. A plurality of suitably disposed openings are pro vided near the center of the fan so that air is admitted to the space between the body member and fan. This air will flow outwardly through the slots in the friction members to carry away the heat generated due to friction. Additionally, this air stream will also carry away undesirable dirt and dust. It is very desirable that these slots be formed in the friction element carried by the driving member because the driving member will reach the higher speeds of the engine which the driven member does not reach. Thus the friction elements carried by the driving member also has a fan action at higher speeds, and the air forced through the slots will effectively carry away the heat generated by friction between the elements.

The unit could be manufactured and packaged as an attachment including the fan, friction elements and body member, which could easily be attached to the shaft of the water pump on a conventional automobile. Such an attachment could either have or be without the accessory driving sheave 34. 1

. In the modified form of Figures 5 and 6, the chamber between the cup member and the fan receives air through the openings 92. The disc shaped friction elements 74 perform a turbine action in expelling the air from the chamber and additionally increase the fans grit and dirt clearance characteristics. Furthermore each disc shaped friction pad can rotate about its rivet connection 76 without changing its friction effect. This serves to uniformly wear each of the friction pads.

The adjusting nut can be used to change the biasing force of the Believille springs. The thermally responsive spring has the same action as the spring in the previous embodiment under changing temperature conditions. It should be noted that the springs are in direct metal to metal contact with the shaft so that the heat of the engine will be directly conducted to the thermally responsive spring. When the engine is cold, the pressure exerted by the springs will be less and the cooling effect of the fan will be decreased due to the increased slippage, and vice versa.

Whereas I have shown and described the preferred form and several modifications of my invention, it should be understood that various other changes could be made. For example, in Fig. 3 I have shown a three-bladed fan; however, any number of blades could be used as in Figure 6. The second pulley for driving a suitable accessory is not absolutely necessary, although I have found it desirable. The accessory to be driven by this pulley, of course, is optional and could be the compressor for an air-conditioning unit, the power-steering drive, the generator, or any suitable accessory. It should be understood that the plane of the friction elements in Fig. 2 could be inclined in either direction. The same is true of Figure 6. The spring could be in the form of a leaf, a coil, or a suitable combination. I therefore wish that my invention be unrestricted except as by the appended claims.

I claim:

1. In a drive for use on an engine driven vehicle or the like adapted to drive an accessory such as a generator, air conditioning compressor, and the like, a body member adapted to be driven by the engine of the vehicle, a fan member rotatably mounted on the body member, axially opposed friction elements on the fan and body member, means for causing slippage between the friction elements above a predetermined speed including a slideable mounting for the fan on the body member, and an accessory connection on the fan.

2. The structure of claim 1 characterized by and including yielding means for biasing the friction elements together.

3. In a fan drive for an engine driven vehicle cooling system or the like, a body member adapted to be driven by the vehicles engine, a fan rotatably mounted on the body member, friction elements between them, means for preventing slippage between the friction elements up to a selected rotative speed and for thereafter initiating slippage, and means responsive to ambient temperatures for changing the selected rotative speed below which slippage does not occur and above which slippage does occur.

4. The structure of claim 3 in which said last mentioned means includes a bimetal element.

5. In a fan drive for an engine driven vehicle cooling system or the like, a body member adapted to be driven by the vehicles engine, a fan on the body member, friction elements between them, means for preventing slippage between the friction elements up to a selected rotative speed, and means responsive to ambient temperatures for changing the selected rotative speed at which slippage starts.

6. In a drive mechanism for use on an engine driven vehicle or the like, abody member adapted to be driven by the engine of the vehicle, a fan member mounted on the body member for both rotary and axial movement, axially opposed friction elements between the fan and body member, means for causing slippage between the friction elements above a predetermined speed, and means for directing an air flow through the axially opposed friction elements to remove the heat developed due to the slippage.

7. The structure of claim 6 further characterized by and including yielding means for biasing the friction elements together.

8. The structure of claim 6 further characterized by and including means responsive to ambient temperatures for changing the predetermined speed above which slippage begins.

References Cited in the file of this patent UNITED STATES PATENTS 1,482,498 Wills Feb. 5, 1924 1,827,039 Ragan Oct. 13, 1931 1,832,726 Newcomb Nov. 17, 1931 2,381,567 Bonham Aug. 7, 1945 

